The present invention relates to an upper vehicle-body structure of a vehicle, in which a roof gusset is attached so as to extend between a center pillar and a roof reinforcement.
In many automotive vehicles, plural roof reinforcements are provided to extend in a vehicle width direction between right and left roof rails extending in a vehicle longitudinal direction, so that the rigidity of a vehicle-body upper portion can be increased. To an upper face of the roof reinforcements is joined a roof panel by a thermosetting adhesive agent, for example.
Further, in many automotive vehicles, a Mohican-roof structure in which a Mohican portion formed in a groove shape is provided along a roof rail is applied to a roof portion thereof. In the Mohican portion, a flange portion of a roof panel and a flange portion of the roof rail are joined together by spot welding.
Moreover, as disclosed in Japanese Patent Laid-Open Publication No. 2010-221825, for example, some vehicles have a vehicle-body structure in which a roof gusset is attached so as to extend between a center pillar and a roof reinforcement provided at the same longitudinal position as the center pillar, so that an impact load inputted to the center pillar from a vehicle side is transmitted to the roof reinforcement via the roof gusset. According to the above-described vehicle-body structure, the impact load inputted to the center pillar can be effectively dispersed to the roof reinforcement, thereby restraining the center pillar from improperly coming into a vehicle compartment.
Meanwhile, in production lines of an automotive vehicle, the vehicle is manufactured through a vehicle-body assembling step, a painting step, and a vehicle assembling step, in order. The vehicle-body assembling step includes a step of assembling a vehicle-body side portion by combining a roof rail with a center pillar, a side sill and others, a step of assembling a vehicle-body upper portion with a roof reinforcement and a roof panel, a step of assembling the above-described vehicle-body side portion and the above-described vehicle-body upper portion, and so on. Accordingly, the above-described adhesion of the upper face of the roof reinforcement and the lower face of the roof panel, or the above-described spot welding of the roof panel and the roof reinforcement at the Mohican portion are conducted in the vehicle-body assembling step. Further, in a case in which the thermosetting adhesive agent is used as the adhesion between the roof reinforcement and the roof panel, this adhesive agent is cured by the heating conducted in the painting step, so that the lower face of the roof panel and the upper face of the roof reinforcement are perfectly joined to each other.
Herein, in the case in which the roof gusset is attached so as to extend between the roof reinforcement and the center pillar, there are two cases: a case where the attaching of the roof gusset is conducted in the vehicle-body assembling step; and the other case where the attaching of the roof gusset is conducted in the vehicle assembling step.
In the case where the attaching of the roof gusset is conducted in the vehicle assembling step, the roof gusset is fixed to the roof reinforcement and the center pillar, respectively, by bolt fastening. In this case, however, there is a concern that when bolts for fixing the roof gusset are fastened to the roof reinforcement in the vehicle assembling step after the thermosetting adhesive agent between the roof reinforcement and the roof panel has been cured in the painting step, the roof panel may have some strain (deformation) which may occur due to a tension or compression of the roof panel that are caused by dimensional errors or inferior fastening by workers.
Meanwhile, in the case where the attaching of the roof gusset is conducted in the vehicle-body assembling step, the roof gusset is attached before the above-described thermosetting adhesive agent has been cured. In this case, in order to improve the production efficiency, the roof gusset is made integrated with a center-pillar side (a vehicle-body side-portion side) by previously welding the outward end portion of the roof gusset to the center pillar directly or via the roof rail before the assembling of the vehicle-body side portion and the vehicle-body upper portion, and then after welding of the Mohican portion, the inward end portion of the roof gusset is fixed to the roof reinforcement by bolts.
In the case where the bolt fastening of the roof gusset is conducted in the vehicle-body assembling step as described above, if the above-described dimensional errors or inferior fastening by workers are within a certain degree, the tension or compression of the roof panel by the roof reinforcement can be properly restrained because of the fluidity of the thermosetting adhesive agent at this moment, so that the strain (deformation) of the roof panel can be prevented properly. Herein, with respect to a welding portion of the roof gusset to the center-pillar side, any inferior fastening by workers may not occur because the welding is conducted by positioning the roof gusset with jigs.
However, in the case where the roof gusset is attached in the vehicle-body assembling step, if the roof gusset is previously made integrated with the center-pillar side for improvement of the production efficiency as described above, a welding gun may interfere with the roof gusset at the time of conducting the spot welding of the Mohican portion for attaching the vehicle-body side portion to the vehicle-body upper portion. Accordingly, there occurs a problem in that a specified portion of the Mohican portion which is covered with the roof gusset from below may not be welded properly.
Herein, while it may be considered that the shape of the roof gusset is changed so as to avoid its interference with the welding gun described above, there is a concern that the rigidity of the roof gusset may decrease improperly depending on its changed shape, so that the function of load transmission from the center pillar to the roof reinforcement by the roof gusset may deteriorate.